RAREST PLANTS PROJECT

Tiny Plants Bind Chaparral Ecology
Several of San Diego County’s rarest and most imperiled plants are benefitting from special attention from The Chaparral Lands Conservancy. The Conservancy’s Rarest Plants Project includes several activities to benefit two particularly rare plants, Orcutt’s spineflower (Chorizanthe oructtiana) and the short-leaved stonecrop (Dudleya brevifolia). Both plants live only in very particular soils near the coast where nearly all of their original habitat has been lost to urban development.

Before work conducted by the Conservancy, Orcutt’s spineflower was only recently known from five populations, four on Point Loma and one at Torrey Pines State Natural Reserve (TPSNR). Starting in 2014, the Conservancy began mapping special soils and conducting field surveys in other suitable habitat to identify any other unknown populations on existing preserve lands. This work resulted in the exciting discovery of seven never before-recorded new populations of the species at several coastal North County preserves thereby greatly improving the conservation status of the species. In addition to mapping and surveys, the Conservancy has worked with the Rancho Santa Ana Botanic Garden to collect and bulk seed to attempt to establish new populations, weeded around existing populations, and installed fencing and signs at several preserves to direct visitors to designated trails and away from delicate spineflower populations.

The short-leaved stonecrop gets its name from the appearance of young plants as similar to nearby pebbles to avoid being eaten by rabbits and other animals. The stonecrop is also only known from just five populations from La Jolla to Del Mar. There are far more individual stonecrop plants than the spineflower at all but one population at the Torrey Pines State Natural Reserve Extension in Del Mar Heights where off-trail trampling by visitors has eliminated most of this population. The Conservancy is working with the San Diego Zoo Institute for Conservation Research to bulk stonecrop seed to establish new populations in suitable habitat at the TPSNR Extension at more remote and less trampled locations. And the Conservancy has installed fencing and signs at several preserves to direct visitors to designated trails and away from vulnerable stonecrop populations.

The Conservancy is also working with the Rancho Santa Ana Botanic Garden and San Diego Zoo Institute for Conservation Research to collect and bulk seed for several other very rare and imperiled species to include in Conservancy habitat restoration projects: California Orcutt grass, little mousetail, Orcutt’s bird’s beak, Orcutt’s brodiaea, Otay Mesa mint, San Diego thornmint, spreading navarretia, and toothed calico-flower.

The Rarest Plants Project has been made possible through the generous support and partnerships with the California Department of Fish and Wildlife, California Department of Parks and Recreation, City of San Diego, Rancho Santa Ana Botanic Garden, San Diego Association of Governments, San Diego Zoo Institute for Conservation Research, Torrey Pines Association, University of California San Diego, and the U.S. Fish and Wildlife Service.